1. Technical Field
Exemplary embodiments of the present invention relate to an image forming apparatus including a chassis that houses a transfer unit, the transfer unit including a plurality of rollers that support an endless belt.
2. Background Art
Conventional image forming apparatuses are constructed of a chassis that houses a transfer unit, which includes an endless intermediate transfer belt, and a sheet feed unit including a sheet conveyance belt.
In general, these image forming apparatus include four photoreceptors, each forming a toner image of one of the colors yellow (Y), magenta (M), cyan (C), and black (K), respectively, and a transfer unit configured as a belt unit. The Y-, M-, C-, and K-toner images formed on respective photoreceptors with a known electrophotographic process are then transferred in a superimposed manner onto the intermediate transfer belt of the transfer unit, thereby forming a full color toner image. In operation, the intermediate transfer belt rotates continuously while contacting all four photoreceptors.
The transfer unit switches the endless intermediate transfer belt between a posture in which the intermediate transfer belt is being conveyed during operation and a posture during replacement, or attachment/detachment of the transfer unit. During replacement, the intermediate transfer belt is separated from all four photoreceptors and the transfer unit can be removed from the image forming apparatus.
In the posture in which the transfer unit can be detached (i.e., during maintenance), the transfer unit is drawn to a proximal side from a relatively wide opening formed in a front wall of the chassis of the image forming apparatus, so that necessary maintenance can be performed. After maintenance, the intermediate transfer belt is attached in the unit attachment posture to the chassis from the front opening.
Although various approaches have been attempted, conventional belt units and image forming apparatuses do not disclose a structure capable of preventing the endless belt from contacting neighboring parts when the endless belt is replaced or attached/detached.